package com.github.pig.common.util;

import java.security.MessageDigest;

/**
 * MD5 加密的工具类
 *
 */
public class MD5Util {

	private static String byteArrayToHexString(byte b[]) {
		StringBuffer resultSb = new StringBuffer();
		for (int i = 0; i < b.length; i++)
			resultSb.append(byteToHexString(b[i]));

		return resultSb.toString();
	}

	private static String byteToHexString(byte b) {
		int n = b;
		if (n < 0)
			n += 256;
		int d1 = n / 16;
		int d2 = n % 16;
		return hexDigits[d1] + hexDigits[d2];
	}

	public static String MD5Encode(String origin, String charsetname) {
		String resultString = null;
		try {
			resultString = new String(origin);
			MessageDigest md = MessageDigest.getInstance("MD5");
			if (charsetname == null || "".equals(charsetname))
				resultString = byteArrayToHexString(md.digest(resultString
						.getBytes()));
			else
				resultString = byteArrayToHexString(md.digest(resultString
						.getBytes(charsetname)));
		} catch (Exception exception) {
		}
		return resultString;
	}

	//sha1 字符串加密    
	public static String getSha1(String str){
		char hexDigits[]={'0','1','2','3','4','5','6','7','8','9','a','b','c','d','e','f'};
    	if(str==null || str.length()==0){
			return null;
		}
		try {
			MessageDigest mdTemp=MessageDigest.getInstance("SHA1");
			mdTemp.update(str.getBytes("UTF-8"));
			byte[] md=mdTemp.digest();
			int j=md.length;
			char buf[]=new char[j*2];
			int k=0;
			for(int i=0;i<j;i++){
				byte byte0=md[i];
				buf[k++]=hexDigits[byte0>>>4 & 0xf];
				buf[k++]=hexDigits[byte0 & 0xf];
			}
			return new String(buf);
		} catch (Exception e) {
    		return null;
    	}
	}


	private static final String hexDigits[] = { "0", "1", "2", "3", "4", "5",
			"6", "7", "8", "9", "a", "b", "c", "d", "e", "f" };

}
